Sintering behaviour and microwave dielectric properties of BaAl2-2x(ZnSi)xSi2O8 ceramics

BaAl2-2x(ZnSi)(x)Si2O8 (x = 0.2-1.0) ceramics were prepared using the conventional solid-state reaction method. The sintering behaviour, phase composition and microwave dielectric properties of the prepared compositions were then investigated. All compositions showed a single phase except for x = 0.8. By substituting (Zn0.5Si0.5)(3+) for Al3+ ions, the optimal sintering temperatures of the compositions decreased from 1475 degrees C (x = 0) to 1000 degrees C (x = 0.8), which then slightly increased to 1100 degrees C (x = 1.0). Moreover, the phase stability of BaAl2Si2O8 was improved. A novel BaZnSi3O8 microwave dielectric ceramic was obtained at the sintering temperature of 1100 degrees C. This ceramic possesses good microwave dielectric properties with epsilon(r) = 6.60, Q x f = 52401 GHz (at 15.4 GHz) and tau(f) = -24.5 ppm/degrees C.